// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/devtools/devtools_agent_host_impl.h"

#include <map>
#include <vector>

#include "base/bind.h"
#include "base/json/json_writer.h"
#include "base/lazy_instance.h"
#include "base/message_loop/message_loop.h"
#include "base/observer_list.h"
#include "content/browser/devtools/devtools_manager.h"
#include "content/browser/devtools/devtools_session.h"
#include "content/browser/devtools/forwarding_agent_host.h"
#include "content/browser/devtools/protocol/page.h"
#include "content/browser/devtools/render_frame_devtools_agent_host.h"
#include "content/browser/devtools/service_worker_devtools_agent_host.h"
#include "content/browser/devtools/service_worker_devtools_manager.h"
#include "content/browser/devtools/shared_worker_devtools_agent_host.h"
#include "content/browser/devtools/shared_worker_devtools_manager.h"
#include "content/browser/loader/netlog_observer.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/content_browser_client.h"

namespace content {

namespace {
    typedef std::map<std::string, DevToolsAgentHostImpl*> Instances;
    base::LazyInstance<Instances>::Leaky g_instances = LAZY_INSTANCE_INITIALIZER;

    base::LazyInstance<base::ObserverList<DevToolsAgentHostObserver>>::Leaky
        g_observers
        = LAZY_INSTANCE_INITIALIZER;
} // namespace

char DevToolsAgentHost::kTypePage[] = "page";
char DevToolsAgentHost::kTypeFrame[] = "iframe";
char DevToolsAgentHost::kTypeSharedWorker[] = "shared_worker";
char DevToolsAgentHost::kTypeServiceWorker[] = "service_worker";
char DevToolsAgentHost::kTypeExternal[] = "external";
char DevToolsAgentHost::kTypeBrowser[] = "browser";
char DevToolsAgentHost::kTypeOther[] = "other";
int DevToolsAgentHostImpl::s_attached_count_ = 0;
int DevToolsAgentHostImpl::s_force_creation_count_ = 0;

// static
std::string DevToolsAgentHost::GetProtocolVersion()
{
    // TODO(dgozman): generate this.
    return "1.2";
}

// static
bool DevToolsAgentHost::IsSupportedProtocolVersion(const std::string& version)
{
    // TODO(dgozman): generate this.
    return version == "1.0" || version == "1.1" || version == "1.2";
}

// static
DevToolsAgentHost::List DevToolsAgentHost::GetOrCreateAll()
{
    List result;
    SharedWorkerDevToolsAgentHost::List shared_list;
    SharedWorkerDevToolsManager::GetInstance()->AddAllAgentHosts(&shared_list);
    for (const auto& host : shared_list)
        result.push_back(host);

    ServiceWorkerDevToolsAgentHost::List service_list;
    ServiceWorkerDevToolsManager::GetInstance()->AddAllAgentHosts(&service_list);
    for (const auto& host : service_list)
        result.push_back(host);

    RenderFrameDevToolsAgentHost::AddAllAgentHosts(&result);

#if DCHECK_IS_ON()
    for (auto it : result) {
        DevToolsAgentHostImpl* host = static_cast<DevToolsAgentHostImpl*>(it.get());
        DCHECK(g_instances.Get().find(host->id_) != g_instances.Get().end());
    }
#endif

    return result;
}

// static
void DevToolsAgentHost::DiscoverAllHosts(const DiscoveryCallback& callback)
{
    DevToolsManager* manager = DevToolsManager::GetInstance();
    if (!manager->delegate() || !manager->delegate()->DiscoverTargets(callback))
        callback.Run(DevToolsAgentHost::GetOrCreateAll());
}

// Called on the UI thread.
// static
scoped_refptr<DevToolsAgentHost> DevToolsAgentHost::GetForWorker(
    int worker_process_id,
    int worker_route_id)
{
    if (scoped_refptr<DevToolsAgentHost> host = SharedWorkerDevToolsManager::GetInstance()
                                                    ->GetDevToolsAgentHostForWorker(worker_process_id,
                                                        worker_route_id)) {
        return host;
    }
    return ServiceWorkerDevToolsManager::GetInstance()
        ->GetDevToolsAgentHostForWorker(worker_process_id, worker_route_id);
}

DevToolsAgentHostImpl::DevToolsAgentHostImpl(const std::string& id)
    : id_(id)
    , last_session_id_(0)
{
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
}

DevToolsAgentHostImpl::~DevToolsAgentHostImpl()
{
    DCHECK_CURRENTLY_ON(BrowserThread::UI);
    NotifyDestroyed();
}

// static
scoped_refptr<DevToolsAgentHost> DevToolsAgentHost::GetForId(
    const std::string& id)
{
    if (g_instances == NULL)
        return NULL;
    Instances::iterator it = g_instances.Get().find(id);
    if (it == g_instances.Get().end())
        return NULL;
    return it->second;
}

// static
scoped_refptr<DevToolsAgentHost> DevToolsAgentHost::Forward(
    const std::string& id,
    std::unique_ptr<DevToolsExternalAgentProxyDelegate> delegate)
{
    scoped_refptr<DevToolsAgentHost> result = DevToolsAgentHost::GetForId(id);
    if (result)
        return result;
    return new ForwardingAgentHost(id, std::move(delegate));
}

bool DevToolsAgentHostImpl::InnerAttachClient(DevToolsAgentHostClient* client,
    bool force)
{
    if (session_ && !force)
        return false;

    scoped_refptr<DevToolsAgentHostImpl> protect(this);
    if (session_)
        ForceDetach(true);
    session_.reset(new DevToolsSession(this, client, ++last_session_id_));
    AttachSession(session_.get());
    NotifyAttached();
    return true;
}

bool DevToolsAgentHostImpl::AttachClient(DevToolsAgentHostClient* client)
{
    return InnerAttachClient(client, false);
}

void DevToolsAgentHostImpl::ForceAttachClient(DevToolsAgentHostClient* client)
{
    InnerAttachClient(client, true);
}

bool DevToolsAgentHostImpl::DetachClient(DevToolsAgentHostClient* client)
{
    if (!session_ || session_->client() != client)
        return false;

    scoped_refptr<DevToolsAgentHostImpl> protect(this);
    InnerDetachClient();
    return true;
}

bool DevToolsAgentHostImpl::DispatchProtocolMessage(
    DevToolsAgentHostClient* client,
    const std::string& message)
{
    if (!session_ || session_->client() != client)
        return false;
    return DispatchProtocolMessage(session_.get(), message);
}

void DevToolsAgentHostImpl::InnerDetachClient()
{
    int session_id = session_->session_id();
    session_.reset();
    DetachSession(session_id);
    io_context_.DiscardAllStreams();
    NotifyDetached();
}

bool DevToolsAgentHostImpl::IsAttached()
{
    return !!session_;
}

void DevToolsAgentHostImpl::InspectElement(
    DevToolsAgentHostClient* client,
    int x,
    int y)
{
    if (!session_ || session_->client() != client)
        return;
    InspectElement(session_.get(), x, y);
}

std::string DevToolsAgentHostImpl::GetId()
{
    return id_;
}

std::string DevToolsAgentHostImpl::GetParentId()
{
    return "";
}

std::string DevToolsAgentHostImpl::GetDescription()
{
    return "";
}

GURL DevToolsAgentHostImpl::GetFaviconURL()
{
    return GURL();
}

std::string DevToolsAgentHostImpl::GetFrontendURL()
{
    return std::string();
}

base::TimeTicks DevToolsAgentHostImpl::GetLastActivityTime()
{
    return base::TimeTicks();
}

BrowserContext* DevToolsAgentHostImpl::GetBrowserContext()
{
    return nullptr;
}

WebContents* DevToolsAgentHostImpl::GetWebContents()
{
    return NULL;
}

void DevToolsAgentHostImpl::DisconnectWebContents()
{
}

void DevToolsAgentHostImpl::ConnectWebContents(WebContents* wc)
{
}

bool DevToolsAgentHostImpl::Inspect()
{
    DevToolsManager* manager = DevToolsManager::GetInstance();
    if (manager->delegate()) {
        manager->delegate()->Inspect(this);
        return true;
    }
    return false;
}

void DevToolsAgentHostImpl::ForceDetach(bool replaced)
{
    if (!session_)
        return;
    scoped_refptr<DevToolsAgentHostImpl> protect(this);
    // Clear |client_| before notifying it.
    DevToolsAgentHostClient* client = session_->client();
    InnerDetachClient();
    client->AgentHostClosed(this, replaced);
}

void DevToolsAgentHostImpl::InspectElement(
    DevToolsSession* session,
    int x,
    int y)
{
}

void DevToolsAgentHostImpl::SendMessageToClient(int session_id,
    const std::string& message)
{
    // Filter any messages from previous sessions.
    if (!session_ || session_id != session_->session_id())
        return;
    session_->client()->DispatchProtocolMessage(this, message);
}

// static
void DevToolsAgentHost::DetachAllClients()
{
    if (g_instances == NULL)
        return;

    // Make a copy, since detaching may lead to agent destruction, which
    // removes it from the instances.
    Instances copy = g_instances.Get();
    for (Instances::iterator it(copy.begin()); it != copy.end(); ++it) {
        DevToolsAgentHostImpl* agent_host = it->second;
        agent_host->ForceDetach(true);
    }
}

// static
void DevToolsAgentHost::AddObserver(DevToolsAgentHostObserver* observer)
{
    if (observer->ShouldForceDevToolsAgentHostCreation()) {
        if (!DevToolsAgentHostImpl::s_force_creation_count_) {
            // Force all agent hosts when first observer is added.
            DevToolsAgentHost::GetOrCreateAll();
        }
        DevToolsAgentHostImpl::s_force_creation_count_++;
    }

    g_observers.Get().AddObserver(observer);
    for (const auto& id_host : g_instances.Get())
        observer->DevToolsAgentHostCreated(id_host.second);
}

// static
void DevToolsAgentHost::RemoveObserver(DevToolsAgentHostObserver* observer)
{
    if (observer->ShouldForceDevToolsAgentHostCreation())
        DevToolsAgentHostImpl::s_force_creation_count_--;
    g_observers.Get().RemoveObserver(observer);
}

// static
bool DevToolsAgentHostImpl::ShouldForceCreation()
{
    return !!s_force_creation_count_;
}

void DevToolsAgentHostImpl::NotifyCreated()
{
    DCHECK(g_instances.Get().find(id_) == g_instances.Get().end());
    g_instances.Get()[id_] = this;
    for (auto& observer : g_observers.Get())
        observer.DevToolsAgentHostCreated(this);
}

void DevToolsAgentHostImpl::NotifyAttached()
{
    if (!s_attached_count_) {
        BrowserThread::PostTask(
            BrowserThread::IO,
            FROM_HERE,
            base::Bind(&NetLogObserver::Attach,
                GetContentClient()->browser()->GetNetLog()));
    }
    ++s_attached_count_;

    for (auto& observer : g_observers.Get())
        observer.DevToolsAgentHostAttached(this);
}

void DevToolsAgentHostImpl::NotifyDetached()
{
    --s_attached_count_;
    if (!s_attached_count_) {
        BrowserThread::PostTask(
            BrowserThread::IO,
            FROM_HERE,
            base::Bind(&NetLogObserver::Detach));
    }

    for (auto& observer : g_observers.Get())
        observer.DevToolsAgentHostDetached(this);
}

void DevToolsAgentHostImpl::NotifyDestroyed()
{
    DCHECK(g_instances.Get().find(id_) != g_instances.Get().end());
    for (auto& observer : g_observers.Get())
        observer.DevToolsAgentHostDestroyed(this);
    g_instances.Get().erase(id_);
}

// DevToolsMessageChunkProcessor -----------------------------------------------

DevToolsMessageChunkProcessor::DevToolsMessageChunkProcessor(
    const SendMessageCallback& callback)
    : callback_(callback)
    , message_buffer_size_(0)
    , last_call_id_(0)
{
}

DevToolsMessageChunkProcessor::~DevToolsMessageChunkProcessor()
{
}

bool DevToolsMessageChunkProcessor::ProcessChunkedMessageFromAgent(
    const DevToolsMessageChunk& chunk)
{
    if (chunk.is_last && !chunk.post_state.empty())
        state_cookie_ = chunk.post_state;
    if (chunk.is_last)
        last_call_id_ = chunk.call_id;

    if (chunk.is_first && chunk.is_last) {
        if (message_buffer_size_ != 0)
            return false;
        callback_.Run(chunk.session_id, chunk.data);
        return true;
    }

    if (chunk.is_first) {
        message_buffer_ = std::string();
        message_buffer_.reserve(chunk.message_size);
        message_buffer_size_ = chunk.message_size;
    }

    if (message_buffer_.size() + chunk.data.size() > message_buffer_size_)
        return false;
    message_buffer_.append(chunk.data);

    if (chunk.is_last) {
        if (message_buffer_.size() != message_buffer_size_)
            return false;
        callback_.Run(chunk.session_id, message_buffer_);
        message_buffer_ = std::string();
        message_buffer_size_ = 0;
    }
    return true;
}

} // namespace content
